European Journal of Endocrinology (2008) 159 275–282 ISSN 0804-4643 CLINICAL STUDY Tachykinins in endocrine tumors and the carcinoid syndrome Janet L Cunningham1, Eva T Janson1, Smriti Agarwal1, Lars Grimelius2 and Mats Stridsberg1 Departments of 1Medical Sciences and 2Genetics and Pathology, University Hospital, SE 751 85 Uppsala, Sweden (Correspondence should be addressed to J Cunningham who is now at Section of Endocrine Oncology, Department of Medical Sciences, Lab 14, Research Department 2, Uppsala University Hospital, Uppsala University, SE 751 85 Uppsala, Sweden; Email:
[email protected]) Abstract Objective: A new antibody, active against the common tachykinin (TK) C-terminal, was used to study TK expression in patients with endocrine tumors and a possible association between plasma-TK levels and symptoms of diarrhea and flush in patients with metastasizing ileocecal serotonin-producing carcinoid tumors (MSPCs). Method: TK, serotonin and chromogranin A (CgA) immunoreactivity (IR) was studied by immunohistochemistry in tissue samples from 33 midgut carcinoids and 72 other endocrine tumors. Circulating TK (P-TK) and urinary-5 hydroxyindoleacetic acid (U-5HIAA) concentrations were measured in 42 patients with MSPCs before treatment and related to symptoms in patients with the carcinoid syndrome. Circulating CgA concentrations were also measured in 39 out of the 42 patients. Results: All MSPCs displayed serotonin and strong TK expression. TK-IR was also seen in all serotonin- producing lung and appendix carcinoids. None of the other tumors examined contained TK-IR cells. Concentrations of P-TK, P-CgA, and U-5HIAA were elevated in patients experiencing daily episodes of either flush or diarrhea, when compared with patients experiencing occasional or none of these symptoms.